Actual notice of the rule shall be given to the plaintiff in the process, or his counsel of record, and to all creditors whose addresses are known to the petitioner; and publication thereof shall be made twice in a weekly newspaper published in the county, and twice in a daily newspaper published in the county, if there be any, and once in the legal periodical, if any, designated by the court, and an affidavit of such service and publication shall be filed in the cause at least three days before the day fixed for the hearing. Notice to creditors non-resident in the county may be made by registered letter.
39 P.S. § 6